# penny

> Shopping aggregator surfacing live prices and availability across many retailers. Catalog data comes from the Channel3 universal product catalog; penny holds no inventory. Prices and stock are verified against retailers and refreshed continuously, never served indefinitely stale.

## Catalog
- Sitemap index: https://penny.shop/sitemap.xml
- Discovered category hubs: https://penny.shop/sitemaps/categories.xml
- Discovered brand hubs: https://penny.shop/sitemaps/brands.xml
- Category page: https://penny.shop/category/{slug}
- Brand directory: https://penny.shop/brands
- Brand page: https://penny.shop/brands/{id}
- Product page: https://penny.shop/products/{id}

## Data provenance
- Source: [Channel3](https://trychannel3.com) universal product catalog — 100M+ products across thousands of retailers; penny holds no inventory and maintains no separate product database
- Catalog & search: product detail, brands, categories, and images all come from the Channel3 API
- Prices & availability: Channel3 aggregates live offers across merchants into a low–high range with an offer count
- Buy links: Channel3-sourced retailer URLs; affiliate/commission-tracked on click-through
- Freshness: Channel3 verifies price and stock on each fetch — product pages within roughly a minute, category grids within hours; penny caches only stable identifiers (product ids, category slugs) long-term (see ADR-0003)